The development of drug delivery devices for implantation into a pre-selected locus in a mammal is ongoing. To date, a variety of surgically implantable drug delivery devices have been developed and are discussed below.
U.S. Pat. No. 4,378,016 describes a surgically implantable device for delivering an active factor, for example, a hormone, to a pre-selected site, for example, the peritoneal cavity, of a mammal. The device comprises a fluid permeable membranous sack for implantation within the mammal and an impermeable hollow tube having one end connected to an opening in the sack and the other end designed to remain outside the body of the mammal. The tube provides an access passageway to the membranous sack, such that after the sack has been surgically implanted into the mammal, a cell containing envelope may be introduced into the sack via the tube. Upon insertion of the cell containing envelope into the sack, the cells may produce an active factor, which subsequently may diffuse into the surrounding tissue or organ of the recipient.
U.S. Pat. No. 5,182,111 describes a surgically implantable device for delivering an active factor to a pre-selected site, for example, a tissue or organ, in a mammal. The device comprises a semi-permeable membrane enclosing at least one cell type that produces a specific active-factor and a second cell type that produces an augmentory factor. The augmenting factor produced by the second cell type subsequently induces the first cell type to produce the active-factor.
U.S. Pat. No. 4,479,796 describes a surgically implantable dispenser for infusing a pre-selected drug directly into the blood stream. Briefly, the dispenser is surgically spliced in line with a blood vessel. The dispenser encloses a replaceable cartridge of cells, for example, micro-organisms, which produce and secrete the drug into blood flowing past the cartridge.
U.S. Pat. No. 4,309,776 describes an intravascular drug delivery device having a chamber containing transplanted cells for surgical implantation into the wall of a blood vessel. The device comprises a porous wall that permits a hormone produced by the transplanted cells to diffuse out of the chamber and into the blood stream.
It is desirable, however, to produce a device that may be implanted into a mammal by either non-surgical or only minimally invasive surgical procedures, and that once implanted the device secretes a pre-selected molecule directly into the vasculature. In addition, it is desirable to produce a device which, when implanted, administers the pre-selected molecule into the mammal over an extended period and may be removed conveniently, if or whenever the necessity arises. Accordingly, it is an object of the present invention to provide an easily implantable device for delivering, over long periods of time, a pre-selected molecule into the systemic circulation of a mammal. It is another object to provide a method for non-surgically implanting the device into a blood vessel of a mammal for delivering the pre-selected molecule into systemic circulation.
These and other objects and features of the invention will be more clearly understood from the description, drawings, and claims which follow.